Package: x2goclient-4.1.2.2-2020.02.13-setup.exe
Version: 4.1.2.2

Dear developers, bringing this to your attention, I experienced the following myself:

Title: x2go "smearing" windows and extremely slow
Link: https://bbs.archlinux.org/viewtopic.php?id=268985

Client machine's OS name: Microsoft Windows 10 Pro
Client machine's OS version: 10.0.19045 N/A Build 19045
Client machine's version of X2GoClient: 4.1.2.2
Relevant settings: Session type XFCE (else using default connection, input/output and media session preferences)
Server's OS: CentOS Stream release 8
Server's version of the x2goserver package: 4.1.0.3-17.el8.1 (@epel)
Server's version of the x2goserver-xsession package: 4.1.0.3-17.el8.1 (@epel)
Server's version of the nxagent package: 3.6.x
Server's version of any other relevant packages:
xfce-polkit.x86_64  0.3-3.el8
xfce4-appfinder.x86_64 4.16.1-3.el8                                          
xfce4-panel.x86_64 4.16.3-1.el8                                          
xfce4-power-manager.x86_64 4.16.0-1.el8                                          
xfce4-pulseaudio-plugin.x86_64 0.4.3-3.el8                                       
xfce4-screensaver.x86_64 4.16.0-3.el8                                          
xfce4-session.x86_64 4.16.0-4.el8                                         
xfce4-settings.x86_64 4.16.5-2.el8                                          
xfce4-terminal.x86_64 0.8.10-2.el8                                          
xfconf.x86_64 4.16.0-1.el8 

Steps to reproduce:
1. Have an updated CentOS Stream release 8 server running (e.g. a KVM) with the latest EPEL Repo, x2goserver-xsession packages and 'Xfce' as dnf groupinstall'ed with -y flag.
2. Have an updated Windows 10 Pro client machine running with the latest x2goclient version, configured to ssh on port 22 to 1. with a RSA/DSA key, auto login via SSH Agent or default SSH key on and a shared folder without filename encoding, but automount and 'use ssh to tunnel filesystem through firewalls' checked.
3. Start a session and experience "smearing" windows, loading and rendering extremely slow when moving them around
4. In the session go to Applications > Settings > Window Manager Tweaks > Compositor
5. Turn off 'Enable display compositing' and close the window. Performance and rendering rather match the preferences now.

Merry X-Mas and have a good day! 

Best regards,

Robert